/Engine/Source/Runtime/Engine/Classes/GameFramework/CharacterMovementComponent.h
On the Server, verify that an incoming client TimeStamp is valid and has not yet expired. It will also handle TimeStamp resets if it detects a gap larger than MinTimeBetweenTimeStampResets / 2.f !! ServerData.CurrentClientTimeStamp can be reset !!
true if TimeStamp is valid, or false if it has expired.
virtual bool VerifyClientTimeStamp ( float TimeStamp, [FNetworkPredictionData_Server_Character](API\Runtime\Engine\GameFramework\FNetworkPredictionData_Server_Ch-) & ServerData )